This invention concerns a novel electrical backplane or "mother board" and a method for making the same.
In telecommunications, biomedical instrumentations, computer systems, and in the data processing industry itself, it is common to use innerconnecting backplane assemblies also known as "mother boards," each having connectors mounted thereon into which printed circuit boards can be inserted. Each printed circuit board is disposed generally perpendicular to the backplane, and further can be merely slipped into or out of its specific connector.
Typically, spring type contacts provided in the connector mounted on the backplane establish electrical continuity at separate terminal areas on the printed circuit board. The printed circuit board can have a printed circuit on one or on both faces, so that the connector would thus have one set or two opposing sets of spring contacts that engage the terminal areas on the respective face of the printed circuit board.
A backplane assembly generally has many receiving contacts, arranged in a grid network, and a number of connectors are generally fitted over and connected to separate groups of these contacts, so that several printed circuit boards may be connected to the backplane and into the circuitry of the device. However, where many printed circuits are transmitted through the backplane, the current carrying capacity of the backplane is quickly reached, so that more than one and frequently many backplanes must be used. This adds costs to the device because of the separate different backplanes needed and the resulting interconnection components needed between the backplanes themselves.
The problem of low current carrying backplanes is readily understood however, since many prior backplane ground and potential planes have been made by coating a layer of copper on a board in the form of a printed circuit, and this coating is very thin. This limits the current carrying capacity generally only to a few amps.